Tobacco product and method of conditioning same



United States Patent TOBACCO PRODUCT AND METHOD 0F CONDITIONING SAMEErnest H. Freund, Sayville, and Kelvin Dornovs, Oakdale, N. Y.,assignors to National Dairy Research Laboratories, Inc, Islip, N. Y., acorporation of Delaware No Drawing. Application March 31, 1955, SerialNo. 498,437

12 Claims. c1. 131-17 This invention relates to tobacco products and amethod of conditioning the same, and more particularly to tobaccoproducts such as cigarettes, cigars, and tobacco treated with alactositol conditioning agent and to the method of conditioning thesame.

Throughout the manufacture and storage of tobacco products, the controlof the moisture content is of special importance. If, in the manufactureof tobacco products, the moisture content falls too low, the tobaccobecomes brittle and forms dust. If, on the other hand, the moisturecontent becomes too high, there is a tendency toward mold formation, orthe creation of a soggy condition. Either condition is highlyundesirable since the tobacco should have a moist texture.

Furthermore, after tobacco products leave the manufacturer, it isdesired that the moisture content be maintained within the properlimits. The product should reach the consumer with such a moisturecontent that it is neither dry or brittle, and not so moist as to be inmoldy or soggy condition.

To this end the manufacturer adds to the tobacco a conditioning agent orhumectant calculated to maintain a proper moisture content of theproduct during fabrication and storage. The humectant should contributeno unpleasant taste, should be nontoxic to the human system, and itscombustion products should be likewise nontoxic.

Among the important properties involved in the selection of aconditioning agent, or in the formulation of a combination ofconditioning agents in case all the desired properties are not presentin a single agent, are volatility, tar formation, hygroscopicity,humectant range, and dynamic hygroscopicity. The volatility should be aslow as possible in order not to change the concentration of theconditioning agent in the tobacco product and to prevent volatilizing ofthe conditioning agent by the combustion of the tobacco. The tarformation should be as low as possible to prevent irritation of thosebody organs which come in contact with the smoke. The amount of waterbound by the conditioning agent should be high.

The humectant range is characterized by the change in Water content of agiven amount of humectant caused by a given change in relative humidity.A low change in Water content is indicative of a narrow humectant range.A narrow humectant range is obviously preferred.

Dynamic hygroscopicity is the rate of change in the moisture content ofa humectant caused by a given change in relative humidity. It isdesirable that this rate be low, since a small change in the moisturecontent of tobacco products is preferred when their package istemporarily opened and they are exposed to atmospheres of widely varyinghumidities.

Other properties of the conditioning agent to be considered are taste,viscosity, chemical reactivity, compatice ibility, melting point,solubility and tendency to form stable supersaturated solutions.

Generally all the requirements of an ideal conditioning agent fortobacco are not found in a single substance. Therefore, mixtures ofconditioning agents are preferably used in order to have a compositeconditioning agent having the most desirable properties.

Heretofore, various humectants have been employed in tobacco productsand they are well described in the literature. For example, FrenchPatent No. 847,099, dated June 26, 1939, describes the use of lithiumsalts, such as lithium chloride, lithium bromide, lithium nitrate andlithium salicylate, as humectants in tobacco products. Tobacco productscontaining a glycosimine humectant are disclosed in U. S. Patent No.2,286,639, issued June 16, 1942. The use of sorbitol as a conditioningagent in tobacco products is set forth in U. S. Patent No. 2,067,338,issued January 12, 1937, while U. S. Patent No. 2,172,357, issuedSeptember 12, 1939, discloses the use of a mixture of hexahydricalcohols, such as sorbitol, iditol, and talitol, as humectants fortobacco products. Hexides which are dihydroxy cyclic inner ethersobtained by the intramolecular loss of two moles of water from thehexitols, are disclosed as humectants for tobacco products in U. S.Patent No. 2,371,389, issued March 13, 1945, and alphamethyl glycerineas an active humectant in tobacco products is described in U. S. PatentNo. 2,483,418, issued October 4, 1949.

In addition to the above humectants, others have been employed, examplesbeing molasses; sugars, particularly invert sugars; glycerol; diethyleneglycol; and propylene glycol. While all of the above humectants havetheir advantages, they also suffer from certain disadvantages notedbelow.-

In view of their cheapness, sugars are used as much as possible but theamounts employed are limited by the fact that they do not impartsufiicient elasticity or life to cigarette tobaccos, theirhygroscopicity is inferior to that of glycerine or glycols, theirchemical reactivity causes undesired changes in their flavoring, andtheir combustion products do not give the most desirable smokingcharacteristics.

Glycerine has more desirable physical characteristics with respect tohygroscopicity, power of imparting springiness or life to a cigarettetobacco, and better performance on spraying. lso, being less reactivethan sugars, it produces less changes in the flavor. However, itscombustion gives rise to the highly irritating acrolein, which not onlyatfects the general smoking quality unfavorably when present in excess,but also, due to its high chemical activity, acts upon the flavoringingredients in the butt portion of the cigarette thus alteringundesirably the smoking characteristics during the later stages of thesmoking period.

Diethylene glycol is advantageous from the standpoint of hygroscopicityand physical quality of the tobacco during the processing of thetobacco, but since it is more volatile than glycerine, diethylene glycolappears in the smoke as such, and hence is absorbed by the system. Inview of the known toxicity of diethylene glycol, its use in tobacco isconsidered by many to be undesirable.

Sorbitol does not yield acrolein on combustion, and does not have thechemical reactivity towards flavoring ingredients of the sugars. Whilesorbitol has a quite narrow humectant range relative to the knownhumectants, an improvement in this respect is still desirable.

Therefore, it is an object of this invention to provide tobacco productswith a humectant which develops only a small amount of tars during itscombustion. Further objects are the provision of a humectant possessinga narrow humectant range in order to maintain the moisture in thetobacco products within narrower limits and the provision of a humectanthaving low dynamic hygroscopicity.

The humectant of this invention is lactositol which may be employedeither solely or preferably in combination with other humectants. Hence,it will be understood that the term a lactositol conditioning agent asused herein refers to either lactositol or lactositol admixed with atleast one other humectant.

Lactositol, or lactitol, the polyhydric alcohol which is obtained by thehydrogenation of lactose, has the follow- It may be prepared either bythe electro-reduction of lactose or by the catalytic hydrogenation oflactose, the latter process being preferred, since it is more economicaland leads to products of higher purity. The preparation of lactositol bythe catalytic hydrogenation of lactose using a nickel catalyst is setforth in Patent No. 1,990,245, issued February 5, 1935. The use of anickel chromate catalyst is described in Patent No. 1,936,999, issuedNovember 28, 1933, while Patent No. 2, 292,293 issued August 8, 1942,discloses the use of accelerating salts and Patent No. 2,421,416, issuedJune 3, 1947, discloses the acceleration by magnesium.

The lactositol conditioning agent may be advantageously incorporatedinto the tobacco in the form of an aqueous solution by any convenientmethod, for example, tumbling, dipping, or spraying, and the treatedtobacco then dried and rehumidified. The amount of the conditioningagent added will depend upon the nature of the tobacco and the desiredhumidity conditions. Generally, from about 0.03 g. to about 0.12 g. ofthe lactositol conditioning agent per gram of tobacco is sufficient togive the tobacco a moist texture although it will be understood that theamount employed is not critical.

Suitable humectants which may be added to lactositol to form lactositolconditioning agents include glycerol, sorbitol, and Arlex, which is amixture of hexitols manufactured by the Atlas Powder Co. and consistingmainly of sorbitol and having a total polyol (polyhydric alcohol)content of about 85%. The amount of each humectant present in thelactositol conditioning agent will depend upon the characteristicsdesired. Typical suitable lactositol conditioning agents include, forexample, 30% lactositol70% glycerol, 50% lactositol-50% glycerol, 75%lactositol-25% glycerol, 50% lactositol-50% sorbitol, and 50%lactositol-50% Arlex. The addition of other humectants to lactositolwill increase the hygroscopicity thereof, enlarge the humectant range oflactositol, and lessen the chance that lactositol will crystallize.

The humectant range and the dynamic hygroscopicity of lactositol, a 2:1by weight mixture of lactositol and glycerol, and sorbitol wasascertained by determining the changes in weight per unit time when anaqueous solution of the humectant is transferred from an atmospherehaving a relative humidity which is in equilibrium with the watercontent of the humectant into an atmosphere which has a higher or lowerrelative humidity.

Table I illustrates the weight gained by these solutions per unit timewhen dispersed on sand and transferred at 75 F. from an atmosphere of32% relative humidity to one of 79% relative humidity,

Table 11 illustrates the weight lost by these solutions when transferredfrom an atmosphere of 58% relative humidity to one of 32% relativehumidity. These solutions were also dispersed on sand.

TABLE II Lactositol ggiig Sorbitol Percent Percent Percent Time TimeTime h h (Hrs) fg (Hrs) gig t (Hrs) Egg 2. 5 5. 5 5 25 5 19. g5 4 7. 52. 8 8 8 11 8 14 29 8 29 ll 29 14 40 8 40 11.25 40 14 Table III showsthe weight lost for the same three solutions when transferred from anatmosphere of 79% relative humidity to one of 32% relative humidity.These solutions were also dispersed on sand.

TABLE III Lactositol figiig sorbitol Percent Percent Percent Time TimeTime m as? use we as From a comparison of the data in Tables I, II, andIII it can be seen readily that lactositol has a narrower humectantrange and a lower dynamic hygroscopicity than the 2:1 mixture oflactositol and glycerol, which in turn has a narrower humectant rangeand a lower dynamic hygroscopicity than sorbitol.

The equilibrium hygroscopicity of lactositol at relative humiditiesbelow 50% was found to be higher than that of sorbitol thus enablinglactositol to keep tobacco products more moist at lower relativehumidities than can sorbitol. Thus at about 30% relative humidity theequilibrium hygroscopicity of lactositol was found to be 9% waterwhereas that for sorbitol is 4.5% water. Such a finding is unexpectedand directly contrary to the predictions made in an article titledHygroscopic agents and their use in cosmetics by Girflin et a1.appearing in the December 1949 issue of the Journal of the Society ofCosmetic Chemists.

In order to determine the amount of tar formed upon combustion oftobacco conditioned with lactositol in comparison with that formed uponcombustion of tobacco conditioned with another humectant, 2.5 g. oflactositol and 2.5 g. of sorbitol were applied respectively to two 10gram charges of tobacco and the composition burned in a smoking machine.Higher concentrations of the humectants than normally used were appliedto the tobacco to allow a more exact determination of the differences.

While generally an addition of 0.06 g. of the humectant per gram of thetobacco would be satisfactory for conditioning purposes, a concentrationof 0.25 g. of humectant per gram of tobacco was used for the tardeterminations.

The smoking machine consisted of a train assembled in the followingsequence: a Pyrex tulip funnel head, containing the tobacco charge ontop of a loose mat of glass wool, connected to a 600 ml. gas washingbottle containing 300 ml. trichloroethylene; a 300 ml. gas washingbottle containing 200 ml. of trichloroethylene; two 200 ml. gas washingbottles containing 150 ml. each of trichloroethylene; a 1 liter gaswashing flask containing 500 m1. of isopropyl alcohol; a solenoid valvecontrolled by an electronic timer switch; an open tube mercurymanometer; a vacuum storage bottle; a Cartesian manostat vacuumregulator; a second vacuum storage bottle; a one-way all glass checkvalve; and a tube to an aspirator.

Ten grams of the humectant-treated moist tobacco were packed lightlyinto the tulip bowl on top of a loose mat of glass wool. The tobacco wasthen ignited with the aid of a microburner and the intermittent suctionof the control system. The suction period was one second, with a holdinginterval of six seconds following each puff. The vacuum during thesuction period was controlled as closely as possible to give an averageof 5 inches of vacuum as measured on a Bourdon gauge placed after thelast gas washing bottle. At the end of the burning period, the air flowwas stopped, the ash and glass wool removed from the tulip, and extratrichloroethylene placed in the tulip and allowed to drain slowly intothe first trap carrying the tar with it.

The contents of each trap was filtered through a medium filter paperinto a two-liter balloon flask and the entire filtrate was evaporatedunder vacuum until only a dark brown viscous residue remained. Thetwo-liter balloon flask containing the vacuum concentrated residue wastreated to a light heating by being jacketed in a double heating mantleconnected to a variable transformer set at 20 volts. A vacuum was pulledon this flask occasionally during the heating period of approximatelysix hours required to remove a golden colored dew which gradually roseup the sides of the flask and was finally largely dispelled. Theremaining residue was essentially nonvolatile and approached constantweight. This material has been considered the tar" fraction. It wasweighed in the balloon flask on a new Ohaus balance which offered areciprocal sensitiivty by the method of swings of approximately 0.05 gm.The Weight of the empty and dry flask was again taken.

In a series of five tar determinations on each of the twohumectant-treated tobaccos, an average of only 0.130 gram of tar wasproduced per gram of lactositol treated tobacco as compared to 0.203gram of tar per gram of sorbitol treated tobacco. The data thus showsthat a lactositol-treated tobacco produces substantially less tar than asorbitol-treated tobacco.

The following two examples illustrate the preparation of tobaccoproducts containing lactositol.

Example 1 Two hundred grams of tobacco were treated with 200 ml. of a 6%lactositol solution by pouring the solution over the tobacco in a largestainless steel tray at room temperature, and then tumbling the tobaccofor more uniform mixing for 60 minutes. This preparation was heated todryness in a circulating oven at F., and rehumidified over a 33.5%sulfuric acid solution in a sealed container for 72 hours. The tobaccoproduct contained 6 grams of lactositol per gram of tobacco.

Example 2 The procedure and amounts given in Example 1 were followedexcept that the lactositol conditioning agent contained 3% lactositoland 3% glycerol. The tobacco product contained 3 grams of lactositolconditioning agent per gram of tobacco.

Various modifications and changes may be made in the invention describedherein without departing from the spirit thereof or sacrificing any ofthe beneficial advantages. Hence, it will be understood that theinvention is to be limited only within the scope of the appended claims.

We claim:

l. A tobacco product containing tobacco and a lactositol conditioningagent in an amount sufiicient to give the tobacco a moist texture.

2. A tobacco product containing tobacco and lactositol as theconditioning agent in an amount sufficient to give the tobacco a moisttexture.

3. A tobacco product containing tobacco and a mixture of lactositol andat least one other humectant as the conditioning agent in an amountsufficient to give the tobacco a moist texture.

4. A tobacco product containing tobacco and a mix ture of lactositol andglycerol as the conditioning agent in an amount sufficient to give thetobacco a moist texture.

5. The process of conditioning tobacco comprising adding a lactositolconditioning agent to tobacco.

6. The process of conditioning tobacco comprising adding lactositol asthe conditioning agent to tobacco.

7. The process of conditioning tobacco comprising adding a mixture oflactositol and at least one other humectant as the conditioning agent totobacco.

8. The process of conditioning tobacco comprising adding a mixture oflactositol and glycerol as the conditioning agent to tobacco.

'9. The process as set forth in claim 5 wherein said resultingconditioned tobacco is dried and rehurnidified.

10. The process as set forth in claim 6 wherein said resultingconditioned tobacco is dried and rehurnidified.

ll. The process as set forth in claim 7 wherein said resultingconditioned tobacco is dried and rchutnidified.

12. The process as set forth in claim 8 wherein said resultingconditioned tobacco is dried and rehurnidified.

Power et a1 Ian. 12, 1937 Swain Oct. 6, 1942

1. A TOBACCO PRODUCT CONTAINING TOBACCO AND A LACTOSITOL CONDITIONINGAGENT IN AN AMOUNT SUFFICIENT TO GIVE THE TOBACCO A MOIST TEXTURE.